The present invention relates to a sheet post-processing apparatus for binding sheets or a bundle of sheets, and an image forming apparatus, such as a copier, a printer or a facsimile device equipped with the post-processing apparatus.
A previous sheet post-processing apparatus that performs a saddle stitching, such as disclosed in Japanese Patent Publication (KOKAI) No. 8-301512, comprises a stopper to position a sheet bundle in the sheet feeding direction, which moves to an operating position and to a retracted position.
Problems, such as large size and high cost, occur in the previous sheet post-processing apparatus because they require dedicated drive sources, such as solenoids, to move the stopper to the operating position and the retracted position.
There are also other problems related to the conventional sheet post-processing apparatus, such as the problem of long processing time, because the feeding of the sheet bundle and the moving of the stitching means are controlled in respectively different time frames.
In view of the foregoing problems, it is an object of the present invention to provide a compact and low-cost sheet post-processing apparatus and an image forming apparatus equipped with the sheet post-processing apparatus built therein.
The present invention is composed of the following structure in order to attain the above-described objects. Briefly, the foregoing object is accomplished in accordance with the present invention for the sheet post-processing apparatus, which comprises stacking means for stacking sheets discharged sequentially out of an image forming apparatus; at least one leading edge restricting member movable between a restricting position to restrict a leading edge of a sheet discharged to the stacking means in a sheet discharge direction and a retracted position to retract from the restricting position; a head unit movably disposed in a direction traversing the sheet discharge direction to drive staples into a sheet bundle; an anvil unit opposingly arranged to the head unit and movingly disposed in a direction traversing the sheet discharge direction to receive and bend staples driven from the head; a feed path disposed between the head unit and the anvil unit for allowing the sheet bundle to pass therethrough; and feeding means for feeding sheet bundles from the stacking means to the feed path.
The head unit and the anvil unit stitch sheet bundles are moved for a specific distance into the feed path by the feeding means. The apparatus further includes means for moving the at least one leading edge restricting member from the restricting position to the retracted position or from the retracted position to the restricting position by moving at least one of the head unit and the anvil unit in a direction traversing the sheet discharge direction.
Also, the foregoing object is accomplished in accordance with the present invention by the sheet post-processing apparatus, which comprises stacking means for stacking sheets discharged sequentially out of an image forming apparatus; at least one leading edge restricting member movable between a restricting position to restrict a leading edge of a sheet discharged to the stacking means in a sheet discharge direction and a retracted position retracted from the restricting position; a head unit movably disposed in a direction traversing the sheet discharge direction to drive staples into a sheet bundle; an anvil part opposingly arranged to the head unit and movingly disposed in a direction traversing the sheet discharge direction to receive and bend the staples driven from the head; a feed path disposed between the head unit and the anvil unit for allowing the sheet bundle to pass therethrough; and feeding means for feeding the sheet bundle from the stacking means to the feed path.
The head unit and the anvil unit stitch the sheet bundle fed for a specific distance into the feed path by the feeding means. The apparatus also includes sheet discharge means for discharging the sheet bundle stitched by the head unit and the anvil unit from between the head unit and the anvil unit. A time frame in which at least one of the feeding means and the sheet discharge means feeds the sheet bundle, and a time frame in which at least one of the head unit and the anvil unit move in the direction traversing the sheet discharge direction overlap with each other.